1. Field of the Invention
This invention relates to autologous blood transfusion and more particularly to an anticoagulant delivery device and method.
2. The Prior Art
Autologous blood transfusion is commonly defined as the return of the patient's blood to his own circulatory system during an active bleeding episode such as encountered in certain forms of surgery. It is well known that conventional homologous blood transfusion involves a high risk of hemagglutination, disease transfer and other undesirable side effects. Hemagglutination is minimized by lengthy and expensive blood cross-match procedures. Even with cross-matching, however, transfusion reactions are undesirably frequent. Presently, there is no known practical way of detecting and preventing transmittal of diseases such as hepatitis through homologous blood transfusion. Autologous blood transfusion has the distinct advantage in that adverse serum reactions are completely eliminated along with other problems suggested above associated with blood transfusions.
While blood replacement through autologous blood transfusion has been demonstrated to be safe and effective, routine use of this technique has not been established. One obvious reason for this failure is the lack of an effective, practical, inexpensive, and efficient method and apparatus for recovering and treating the blood for reinfusion.
During the collection phase, one of the most vital considerations is the prevention of coagulation of the aspirated blood. It is known that blood quickly commences to initiate coagulation upon exposure to the atmosphere or contact with a foreign body. Accordingly, devices for aspirating blood wherein anticoagulant is introduced into the blood at a substantial distance from the point of blood entry tend to permit unnecessary blood coagulation. An example of such a device is disclosed in U.S. Pat. No. 3,807,401.
Another system for preventing blood coagulation includes chamber anticoagulation which involves the constant surveillance and administration of anticoagulant to a collection chamber. This technique does not prevent clot formation in the vacuum line between the suction tip and the collection chamber. Further, devices which introduce rapid pressure change and/or abrade the blood cells cause hemolysis of the blood making it undesirable for reinfusion purposes.
Wands which are used to aspirate blood during surgery for removal to a remote container are well known in the art. They conventionally include a handle, aspiration tip and a long conduit into which a vacuum is introduced to draw aspirated blood to the container. Until this present invention, there has been no practical way to introduce anticoagulant into the blood without hemolysis or other undesirable side effects.